The present invention relates to a kind of rangefinders, and more particularly, to a multifunction rangefinder capable of measuring distance, compass location and/or altitude.
In conventional pulse laser rangefinders, current noise is produced during measurement. After conversion to time domain, the location of the current noise is 7˜10 meters from the rangefinder such that noise and true signals cannot be differentiated within 10 meters. To address this problem, small signal noise can be eliminated using a high reference voltage level provided by a single comparator. However, this method also eliminates the small signal pulse needed for long-distance measurement, such that a distant target cannot be measured.